Conduit construction



n 1952 L. H. FRITZBERG 2,599,325

CONDUIT CONSTRUCTION Filed NOV. 22, 1946 Patented June 3, 1952 UNITED vs'rsres PATENT OFFICE CON'DUIT CONSTRUCTION 7 Lawrence 'H. Fritzberg, MinneapoliavMinn.

Application November 22, 19.46, Serial No. 711,775

This invention relates to conduit constructions, and more particularly to conduits adapjtedfor use in heatexchange units.

One ofthe objects of the invention is to provide aconduit structure or an attachment for conduits wherein means is provided to prevent the conduit from being ruptured'from theexpansion of liquids therein due to variation in temperatures. For instance cooling coil heat exchangers which utilize water as an internal cool--' ing'mediumin a tube are-used in air'con'ditio'ning systems. Such coils are frequently subjected to abnormally low temperatures when cold outside air is taken into the system. The freezing of-the water and rupturingpfthe tube or pipes results through the omission of preheaterson' their iailure, failure of the'heating'medium or Stratification of air at freezing temperatures.

Ordinarily to protect :thesecoils against freezing it is necessary to take the coils apart and zo sired amount "of non-freezing "solution =may not reach all parts of the coil. Blowing out the coils also notentirely efiective-because ofcapillary attraction within the tube.

I propose to provide a compressible member whichwill allowfor the expansion of water upon freezing so-that the strength of the tubes or pipes will-not be affected. The compressible member or its support is further so constructed and arranged as to agitate the liquid in the conduit to someextent as it flows through them, and it has beenfound that I can'use a lower liquid velocity to secure the same heat transfer as that of a plain tube or other conduit at a higher velocity.

The above and other objects and advantages of the invention will more fully appear from the following description made in connection with the accompanying drawings, wherein like reference characters refer to the same parts throughout the views, and, in which:

Figure 1 is a view partially in side elevation and partially in longitudinal vertical section of an embodiment of the invention installed in a tube or other conduit;

Figure 2 is a transverse vertical sectional view of the structure of Figure 1;

Figure 3 is a view partially in side elevation and partially in longitudinal vertical section of another form of the invention;

Ward each other.

-14 Claims. (Cl.- 138-28) Figure 4 is a transverse vertical section through the structure of Figure -3;

Figure 5 is a view partially in side elevation and partially in longitudinal vertical sectionof a thirdform'of the invention; and

Figure 6 Ba transverse vertical sectional'view through the structure of Figure 5.

In Figures 1 and 2 there'is shown a conduit-I which; if used in an ordinary heat exchange unit,

that liquid can flow-relatively'f-reely throug-h said conduit while at the same time -a certain -amount of -turbu lence or a itation is imparted thereto.

In the event the liquid such as water which passes through the I conduit 8 is subjected to less than-normal temperatures for which the apparatus is designed and thel-iquid'freezes, the eirpansionthereof 'will' compress the yieldable material 1 0 and press -themetal side strips "-9 inwardly-to- The degree of normal com- }pressive movement of the material ill obviously would be ascertained so that if the water in the conduit 1 should freeze solid there would "be sufficient compressibility'of the-material -.lflto prevent '-rupturing-- strain on the conduit: The

metal strips 9 are provided to hold the cornpressible member improper-shape in the conduit.

Not only does the element made-up of the members 9 andlfl eliminate rupturing due to expansion when the liquid freezes, but is sufiiciently agitates the liquid passing through the conduit to increase the internal heat transfer of the liquid through the conduit and it permits a lower velocity of liquid to compensate for the increased pressure drop due to friction as compared to a plain conduit without a compressible member therein.

In Figures 3 and 4 there is shown a conduit 1 1 within which is located a flattened hollow elongated tubular element I2 between the side walls of which is positioned an elongated rubber element l3. The outer sides of the flattened tubular element 12 are provided with oppositely directed and staggered angular vanes 14 which are directed outwardly and in a direction of flow of liquid through the conduit, such direction being indicated by arrows. Extending outwardly from the outer edges of the vanes [4 are legs 15 which, as best shown in Figure 4, are adapted to position the flattened tubular element [2 centrally in the conduit II.

The flattened tubular element I2 is capable of being compressed when liquid in the conduit H expands in freezing and as the sides of the tubular element l2 are compressed toward each other they will in turn press the elongated rubber filler l3 somewhat in the manner of the pressure of the metal strips 9 lying on either side of the compressible element 10 in Figures 1 and 2. The vanes [4 create a turbulence or an agitation of liquid flowing through the conduit, and the legs l5, as stated, are provided to position the unit in the conduit approximately in the center thereof.

In Figures 5 and 6 I, show a conduit 18 having one of a series of frusto-conical helices ll therein, the base I8 of the helix being approximately as large as the inner diameter of the conduit I6. It is preferred that the helix base l8 be capable of yieldable construction so that it will closely fit the inside of the pipe and may be adapted for pipes of slightly varying diameters. The upper end I!) of the helix I1 is the smaller end and forms an aperture through which an elongated compressible rod-like element 20 extends, the compressible element having a, stiffening wire 2| passing through its center as shown. It is intended that the helical support I! be placed at suitable intervals to maintain the compressible rod-like element 20 in the approximate center of the conduit I6.

The rod-like element 20 permits expansion of the freezing liquid without damage to the conduit and the helical support I1 for said rod-like element 20 not only serves as a support but as means for creating agitation or turbulence of liquid flow through the conduit for the purpose described above.

From the foregoing description it will be seen that I have provided a unit which is insertable in a conduit or combinate of such a unit and a conduit which allows for expansion of a freezing liquid inside the conduit without damage thereto. The uncompressed bulk of the compressible element so limits the cross sectional flow area of the conduit that when liquid therein freezes and expands the compressible element will be reduced in size and the walls of the conduit will remain undamaged. It is also clear from the description above that the entire unit inserted in the conduit is so constructed that it will create a turbulence of flow which increases the internal heat transfer capacity of the liquid as it passes through the conduit.

It will, of course, be understood that various changes may be made in the form, details, arrangement and proportions of the various parts without departing from the scope of my invention.

What I claim is:

1. In a conduit construction, a conduit section through which a liquid is adapted to pass, a flattened hollow tubular element lying generally longitudinally in said conduit, the walls of said element being flexible inwardly toward each other, and a compressible material placed within the tubular element, said element having outwardly directed vanes extending in the direction of fluid flow to agitate fluid flowing in the conduit, at least some of the vanes terminating in leg members to support the element in the conduit.

2. A conduit construction according to claim 1 in which the vanes are oppositely directed and staggered, the legs extending outwardly from the outer edges of the vanes to contact the inner walls of the tubular element.

3. A conduit construction according to claim 1 in which in cross-section one wall of the element is convex and the opposite wall of the element is concave.

4. A device for use in a liquid conduit which comprises a unit adapted to be placed in the conduit and having a portion thereof composed of an elongated mass of compressible material, a resilient relatively rigid framing for the compressible mass comprising a flattened, hollow tubular element enclosing the mass and. having outwardly directed vanes to agitate fluid flowing in the conduit, the compressible mass filling only a portion of the space within the element, and support members to support the framing in place within the conduit.

LAWRENCE H. FRITZBERG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

